Vector Biology & Control Proiect Telex 248812 (MSCi UR) 1611 North Kent Street, Suite 503 Cable MSCI Washington, D.C. Arlington, Virginia 22209 (703) 527-6500 & VECTOR BIOLOGY & CONTROL TRIP REPORT A VISIT TZ- USAID/NEPAL TO STUDY AND IDENTIFY CULICINE FAUNA NOVEMBER 1'i - DECEMBER 27, 1987 by Richard F. Darsie, Jr., Ph.D. and Shreedhar P. Pradhan, H.F.P. AR-061 Managed by Medical Service Corporation International under contract to the US. Ager.cy for International Development Authors Richard F. Darsie, Jr., Ph.D., is a Research Entomologist at The International Center for Public Health Research, University of South Carolina, McClellanville, South Carolina. Shreedhar P. Pradhan, H.F.P., is a Long-Term Malaria Advisor for USAID/Kathmandu. Acknowledgements Preparation of this document was sponsored by the Vector Biology & Control Project under Contract No. DPE-5948-C-00-5044­ 00 to Medical Service Corporation International, Arlington, Virginia, U.S.A., for the Agency for International Development, Office of Health, Bureau of Science and Technology. The authors are indebted to Dr. David Calder for his foresight in fostering the study and his encouragement, to Dr. K.M. Dixit, Chief, NMEO, and R.G. Baidya, Chief, Entomology Section, NMEO, for assigning the entomological team, K. Kadaka, H.P. Poudyal and N.P. Shrestha, for their assistance and diligence in searching for mosquitoes; to P. Xarna and A. Singh for providing accommodations for the study; to N.K. Gurung for assistance in the use of the piggeries, and to M. Chamlin for logistical support. TABLE OF CONTENTS I. INTRODUCTION 1 A. Briefings at USAID and NMEO 1 B. Background 1 C. Preparing a List of Mosquitoes of Nepal 2 II. ACTIVITIES IN NEPAL 3 A. Field Trip to Eastern Nepal (November 23 - December 1, 1987) 3 B. Keys for the Identification of Nepal Mosquitoes 3 C. Preparation of a Manuscript on New Records 3 D. Preparation of Keys with Illustrations 4 E. Training Course in Use of New Keys 4 F. Literature Cited 5 G. Addendum - Training of Mr. Shreedhar P. Pradhan 5 ANNEXES 1 REPORT ON FIELD TRIP TO EASTERN NEPAL NOVEMBER 25 - DECEMBER 1, 1987 2 KEYS TO THE MOSQUITO SPECIES KNOWN TO OCCUR IN NEPAL (DIPTERA, CULICIDAE) 3 NEW MOSQUITO RECORDS FOR NEPAL (DIPTERA, CULICIDAE) 4 ILLUSTRATED KEYS TO THE GENERA OF ADULT FEMALE MOSQUITOES OF NEPAL 5 ILLUSTRATED KEYS TO THE GENERA OF FOURTH INSTAR LARVAE OF THE MOSQUITOES OF NEPAL 6 ILLUSTRATED KEYS TO THE ADULT FEMALES OF THE SUBGENERA OF CULEX AND SPECIES OF SUBGENUS CULEX 7 ILLUSTRATED KEYS TO THE FOURTH INSTAR LARVAE OF THE SUBGENERA OF CULEX AND THE SPECIES OF THE SUBGENUS CULEX OF NEPAL I. INTRODUCTION A. Briefinqs at USAID and NMEO To explain the purpose of the visit and the proposed work plan during the next two months, the following meetings were held: USAID/HFP with Dr. David Calder, Chief, HFP; Drs. Lerry Lacey and Barry Silverman, Vector Biology & Control (VBC) Project; and Mr. S.P. Pradhan, HFP Entomologist. USAID Deputy Director, Mr. William Stacey Rhodes, with Dr. Calder and Mr. Pradhan. NMEO/GON with Dr. K. Dixit, Chief, NMEO; Drs. Lacey and Silverman; Mr. Riddi Gopal Baidya, Chief, and Mr. Jitendra Shrestha of the NMEO Entomology Section; and Mr. S.P. Pradhan. Ministry of Health (MOH), GON, Acting Secretary, Mr. Basu Dev Pradhan, with Drs. Lacey and Silverman, Dr. K. Dixit and Mr. S.P. Pradhan. A ful.L report of the trip and its results can be seen in Annex 1. B. Background Since 1978, outbreaks of mosquito-borne Japanese encephalitis (JE) have occurred in the terai zone of Nepal (Pradhan, 1981; Khatri et al., 1983; Leake et al. 1983). From that year until 1984, a total of 2508 cases with 886 deaths (35.3%) were recorded in Nepalese hospital case records (Khatri et al. 1984). An additional 275 cases were reported just from Sunsari and Morang Districts of Eastern Nepal in 1985 by Leake et al. (1985). Therefore, there is no doubt that JE is a serious problem in Nepal. Studies of epidemics of this disease and subsequent investigations on its epidemiology have confirmed that it is transmitted by mosquitoes. The principal vectors are species belonging to the genus Culex. In fact, Cx. tritaeniorhynchus, a species very common in Nepal at the lower altitudes has been most often incriminated as the main carrier. 2 Despite the knowledge of vectors of JE in other countries, no species has yet been incriminated in Nepal. Nor is there any reliable means of identifying candidate mosquitoes, for they belong to the subfamily Culicinae. Over the past 25 years, the development of keys and the recognition of species have been concentrated in subfamily Anophelinae because it has been malaria ana its vectors that have received major attention. VBC was asked to employ a consultant to study the local mosquito fauna and develop the capacity to identify species belonging to the culicine fauna. C. Preparinq a List of Mosquitoes of Nepal By means of a prelininary review of the literature, including a scientific article coauthored by the writer (Joshi st al. 1965), a list of 98 species was compiled. The list was not finalized until after a field trip had been made to Eastern Nepal by S.P. Pradhan and R.F. Darsie. Results of field collections and identification of specimens, which had been collected and preserved by Mr. Pradhan since 1980 after JE had become a disease problem in Nepal, augmented the list. As a consequence, 16 new country records have been established. The revised list of the mosquitoes known to occur in Nepal is included in Annex 2. It must be said here that Mr. Shreedhar Pradhan deserves considerable credit for maintaining the original collection on which our 1965 report was based and by his dedication and interest in mosquito taxonomy, his continuing efforts to collect and preserve specimens and keep them in good condition. when JE was recognized in Nepal and the need to identify culicine mosquitoes arose, Mr. Pradhan was able to fill that need through his own private and unofficial work on the culicine fauna over the years. 3 II. ACTIVITIES IN NEPAL A. Field Trip to Eastern Nepal - Nov. 23 - Dec. 1, 1987 A full report of this trip and its results can be seen in Annex 1. Collections of mosquitoes were primarily concentrated in piggeries at the Tarahara Agricultural Farm, Sunsari District, because pigs are known reservoirs cf JE virus. By sampling the mosquitoes attracted to and feeding on these hosts, one has indirect evidence of which species could (1) maintain the zoonotic cycle ot JE in nature and (2) act as vectors to spread the disease to humans. At this season, the species most numerous in the pig pens were Cx. fuscocephala, and second Cx. tritaeniorhynchus, a recognized vector of JE in other countries. Among the accomplishments on this trip was the trapping of five different species which proved to be new country records, two in Culex and three in Uranotaenia. Another purpose of the trip was to demonstrate to the Nepalese entomologists the individual rearing technique, a method which provides the best possible specimens for identification. With it one has the larva, pupa and adult of the same individual mosquito which offers three chances to identify it. A total of 55 rearings were completed. B. Keys for the Identification of Nepal Mosquitoes The main effort of the visit has been to develop reliable keys for the identification of adult females and fourth instar larvae. This has been accomplished, and a copy is attached in Annex 2. By the use of my own rather extensive library, it has been possible to formulate keys to all 114 species. One problem which always arises when devising such keys is the number of species in which a stage to be keyed has never been described. Surprisingly few species in the Nepal fauna present this problem. All of the adult females have adequate descriptions, while only five species have larvae unknown. Besides the keys, a glossary was prepared and morphology of both adults and larvae was illustrated and appended to the document for the better understanding of the users. C. Preparation of a Manuscript on New Records It seemed advisable to write up for publication a manuscript detailing the 13 new country records (Annex 3). Locality data, dates of collection and biological notes on many of these species 4 were largely in the head of Mr. Pradhan. Now we have the information written dcwn and voucher specimens properly labelled and ready for me to carry to the Smithsonian Institution. Eventually the manuscript will be submitted to the Journal of the American Mosquito Control Association for publicaticn. One redeeming feature of these collections, especially those which were made in Eastern Nepal during this visit, is that now only three species of Culex, our target genus, which are suppose to occur in Nepal, have yet to be collected. This has been determined by reviewing the Culex literature and noting the known distribution of the species. D. Preparation of Keys with Illustrations Funds were provided by VBC to hire an artist to prepare illustrations for some of the important keys. It was deemed important to work on the generic keys first. Both the adult female and fourth instar larval keys have been finished; see Annexes 4-7. Then the keys to the genus Culex were worked on. It was gratifying to realize that it was possible to find good illustrations for all the key characters in the subgeneric Culex key and for the 19 species included in the subgenus Culex, both adults and larvae.